RFID transponders, either active or passive, are typically used with an RFID transceiver or similar device to communicate information from the transponders. In order to communicate, the transceiver exposes the transponder to a radio frequency (RF) electromagnetic field or signal. In the case of a passive transponder, the RF electromagnetic field energizes the transponder and thereby prompts the transponder to respond to the transceiver by modulating the field in a well-known technique called backscattering. In the case of an active transponder, the transponder may respond to the electromagnetic field by transmitting an independently powered reply signal to the transceiver.
Problems can occur, however, when the RFID transceiver and RFID transponder are confined within the space of an interior housing, such as that of a printer or other apparatus. For example, nearby metallic housing can cause interference and degradation of the magnetically sensitive near field patterns passed between the RFID transceiver and RFID transponder. The interior of the housing may constrain the spatial arrangement of the RFID transceiver and RFID transponder, thus limiting the available space and locations of the near field interrogation region. When the RFID transponder is disposed within the interior of a ribbon supply roll of a printer, the near field interrogation signal may become attenuated when propagating through the ribbon supply roll, and thus more input power is needed for the RFID transceiver to activate the RFID tag. In yet another example, RFID transponders attached to moving elements may have degraded or intermittent communicability with the near field interrogation signals.